JP5811827B2 - Pretreatment liquid - Google Patents

Description

  The present invention relates to a pretreatment liquid used for ink jet recording.

Ink jet recording methods have been rapidly spreading in recent years because they can record color images on plain paper and have low running costs. However, this method has a problem that depending on the combination of the ink and the recording medium, an image defect typified by character bleeding (hereinafter referred to as feathering) is likely to occur, and the image quality is greatly deteriorated.
Therefore, attempts have been made to suppress feathering by suppressing ink permeability. In this case, however, the drying property of the ink deteriorates, and when the recorded matter is touched, the ink adheres to the hand or the image is stained. End up.
In addition, when recording a color image by the ink jet recording method, since inks of different colors are successively stacked, the color ink is smeared or mixed at the color boundary portion (hereinafter referred to as color bleed), There is also a problem that the image quality is greatly reduced.
For this problem, attempts have been made to suppress color bleed by increasing the permeability of the ink, but in this case, the colorant enters the inside of the recording medium, resulting in a decrease in image density or recording. The ink oozes out to the back side of the printing medium, making it impossible to perform duplex printing well.

In order to solve these problems at the same time and improve the image quality, an image forming method using a pretreatment liquid and ink has been proposed.
For example, an ink jet recording method using an aqueous ink containing a pigment and a resin emulsion and a pretreatment liquid containing a polyvalent metal salt and a water-soluble polyallylamine having a polarity opposite to that of the ink has been proposed (see Patent Document 1). ).
Patent Document 2 discloses a pretreatment liquid containing a water-soluble cationic polymer selected from a polyamine-epihalohydrin copolymer, a polyamide-epihalohydrin copolymer, and a polyamide polyamine-epihalohydrin copolymer and water. . Even if aggregation occurs due to the reaction of the pigment with respect to the pigment ink, the pigment is diffused and the vehicle is quickly diffused. As a result, there is no smear fixing property, feathering and color bleeding, and an image with excellent image quality. It has been shown that can be formed.

The method of Patent Document 1 has a problem in terms of drying and fixing properties of aqueous ink on a recording medium. That is, when the pretreatment liquid is deposited on the recording medium and then recorded with the water-based ink, the pigment and the resin emulsion in the ink agglomerate violently. The liquid component is deposited on the outermost surface of the recording medium in a state where it is slightly contained. The accumulated pigment agglomerates are mechanically weak and can be easily removed by rubbing with a finger. Therefore, when the user's hand gets dirty with ink, or when the printed materials overlap, the ink is transferred to the back of the printed materials. A malfunction occurs.
In addition, since water-soluble polyallylamine has a strong cohesive force, the dye component in the dye ink aggregates to cause a hue change, resulting in a color tone different from the color design.
Furthermore, when the formed image was analyzed and the reaction between the ink and the pretreatment liquid was analyzed, it was found that the dot diameter was reduced as the reaction between the pigment and the pretreatment liquid proceeded and aggregated. In other words, although the image density is improved to some extent on plain paper, the pretreatment liquid has a strong cohesive force, so the dots are too small and the side effect of white streaks (portions where no ink adheres) appears in the solid image area. .

Since the cationic polymer used in the pretreatment liquid of Patent Document 2 uses halogen ions as counter anions, there is a problem that a member touching the pretreatment liquid is corroded and rust is mixed in the pretreatment liquid. In addition, when sending paper coated with pretreatment liquid, the pretreatment liquid adheres to metal parts such as spur rollers, and corrosion progresses from the adhesion part and rust is generated, and this rust adheres to the printing surface. There is a problem that a yellow mark is left and the printed surface is stained.
Accordingly, an object of the present invention is to provide a pretreatment liquid for use in new ink jet recording which solves the problem of cohesive strength of water-soluble polyallylamine and the problem of metal corrosion caused by halogen ions in the prior art.

The above problem is solved by the following invention 1).
1) A pretreatment liquid used for ink jet recording, comprising at least a cationic polymer comprising diallylamine organic acid salt and (meth) acrylic acid amide as constituent components, a water-soluble organic solvent, and water.

  ADVANTAGE OF THE INVENTION According to this invention, the pre-processing liquid used for the inkjet recording which solved the problem of the cohesive force of water-soluble polyallylamine, and the problem of metal corrosion by a halogen ion can be provided.

The figure for demonstrating the effect by the pre-processing liquid of this invention. FIG. 3 is a diagram illustrating an example of a recording apparatus that forms an image by scanning an inkjet recording head. FIG. 4 is a diagram illustrating another example of a recording apparatus that scans an inkjet recording head and forms an image. Schematic of the apparatus which apply | coats a pretreatment liquid.

Hereinafter, the present invention will be described in detail.
The present invention includes the following inventions 2) to 5) as preferred embodiments of 1).
2) The pretreatment liquid according to 1), which contains acrylamide as the (meth) acrylic acid amide.
3) The pretreatment liquid according to 1) or 2), wherein the organic acid includes a hydroxy acid.
4) The pretreatment liquid according to any one of 1) to 3), further comprising an organic acid ammonium salt or an organic acid amine salt.
5) The pretreatment liquid according to 4), wherein the organic acid ammonium salt or organic acid amine salt is an ammonium lactate salt or an amine lactate salt.

<Pretreatment liquid>
The pretreatment liquid (hereinafter sometimes referred to as pretreatment liquid) used in the ink jet recording of the present invention includes at least a cationic polymer having a diallylamine organic acid salt and (meth) acrylic acid amide as constituents, a water-soluble organic solvent, and water. And an additive such as an organic acid ammonium salt, an organic acid amine salt, a foam suppressant, a surfactant, a preservative, and a rust preventive as necessary.
Since the pretreatment liquid of the present invention does not contain a large amount of inorganic anions, the metal member is less likely to corrode and the cohesiveness can be reduced by using an organic acid salt as a diallylamine salt having a cohesive strength that is too strong. As a result, since the pigment can be aggregated mildly, an image-formed product having good smear fixability, high optical reflection density, and reduced feathering and color bleeding can be obtained. The reason why such an effect is obtained will be described with reference to FIG.

When ink jet ink (hereinafter sometimes referred to as ink) is landed on the recording medium 102 to which the pretreatment liquid 101 is applied, the salting-out effect by the pretreatment liquid 101 is mild, so the surface of the recording medium 102 The pigment does not agglomerate on the top, and the pretreatment liquid causes dot spreading in the horizontal direction of the recording surface. Thereby, the narrowing of dots is suppressed and the optical reflection density is improved.
Next, when the ink is absorbed by the recording medium 102, the vehicle 103 contained in the ink quickly penetrates into the recording medium, whereas the ink containing an anionic component has a cationic polymer. Or by ion exchange with an organic acid ammonium salt or an organic acid amine salt.
In this way, the pigment 104 is fixed at a relatively shallow position inside the recording medium, so that the optical reflection density is improved and the feathering and color bleeding of the image formed product are reduced. Furthermore, since the pigment is fixed inside the recording medium, a large amount of pigment is not laminated on the surface of the recording medium when an image is formed.

—Cationic Polymer A feature of the cationic polymer used in the present invention is that diallylamine organic acid salt is a structural unit of a cationic function.
Conventionally, diallylamine has been used as a component of the cationic polymer, but it is common to carry out a radical reaction in an aqueous solution after neutralization with a halogen acid. The radical polymerization of diallylamine is a cyclization polymerization reaction involving an intramolecular cyclization reaction, and unless it is neutralized with a strong acid such as a halogen acid, the reactivity is lowered and the polymerization cannot be performed successfully.
Therefore, in many examples, diallylamine hydrochloride and its derivatives are used. When a special salt such as acetate is required, after polymerization reaction using diallylamine hydrochloride, sodium hydroxide or the like is used. Since the neutralization salt is desalted using electrodialysis and then desalted, and then converted to an acetate salt, the production cost is high.
On the other hand, since the cationic polymer used in the present invention can be obtained by copolymerizing diallylamine and a monomer having a higher reactivity than this, the conventionally expensive diallylamine organic acid salt-containing polymer is used at low cost. It became possible to do.

As the monomer having higher reactivity than the above diallylamine, a monomer group having an acrylic acid or methacrylic acid skeleton is desirable, and acrylic acid amide, methacrylic acid amide, N, N-dimethyl is particularly preferable in terms of water solubility, polymerizability, and ionicity. Amides such as acrylamide and acrylic acid-2-hydroxyethylamide are preferred.
These amides are ionically neutral, and there is little concern of forming intramolecular crosslinks or intramolecular complex salts when polymerized. In addition, since amides are often hydrophilic, they can be present in an aqueous solution together with a water-soluble diallylamine organic acid salt and easily copolymerize during the reaction. Among these monomers, acrylamide is more preferable because it has a small molecular weight and can easily obtain an effect when added in a small amount, and can easily increase the cation concentration per polymer solid content.

Examples of the polymer polymerization method include ionic polymerization and radical polymerization. From the viewpoint of aggregability with respect to a dye, a polymer obtained by cyclopolymerization is preferable, and thus radical polymerization that causes cyclopolymerization is preferable.
Examples of the compound that undergoes cyclopolymerization include diallylamine compounds. In the case of an allyl compound, radical deactivation due to proton elimination at the allylic position occurs during radical polymerization, and the polymerization reaction tends to stop. However, the diallylamine-based compound performs an intramolecular cyclization reaction faster than the proton elimination at the allylic position, and can maintain the radical without causing the proton elimination, so that the polymerization reaction can be continued. Therefore, the reactivity is high among allyl compounds having poor polymerization reactivity. However, the polarization due to the strong hydrophilicity of the amine moiety and the hydrophobicity of the allyl group changes depending on the pH, and ion dissociation occurs in the aqueous solution of strong acid, causing strong polarization in the molecule. The position tends to be close, and the intramolecular cyclopolymerization unique to diallylamines easily proceeds. In the case of an organic acid, since there is little ionic dissociation, the number of polarized monomers decreases and intramolecular cyclopolymerization hardly occurs. In that case, a radical termination reaction due to elimination of hydrogen at the allylic position is likely to occur like a general allyl group-containing monomer, and the molecular weight is reduced. Therefore, it is preferable to proceed the reaction using a copolymerization monomer also in the sense of extending the molecular chain length.

  As a polymerization method, it is preferable to neutralize diallylamine with an equimolar amount or more of organic acid to make an aqueous solution, and then raise the temperature to perform radical polymerization. Conditions such as monomer concentration, addition of copolymerization monomer, addition of initiator, etc. are changed according to the molecular weight of the polymer to be obtained and the diallylamine ratio. Although the molecular weight can be controlled by adding a chain transfer agent, diallylamine is an allyl compound in the first place and does not have high polymerizability, and the molecular weight is difficult to increase by itself. When the molecular weight is further reduced, an allyl compound such as sodium methallyl sulfonate is preferably copolymerized. Further, the polymerizability can be changed by addition of a transition metal for chain transfer, and the molecular weight can be controlled.

Examples of the organic acid constituting the diallylamine organic acid salt include lactic acid, acetic acid, glycolic acid, formic acid, citric acid, and malic acid. Of these, lactic acid is preferred.
Unlike diallylamine hydrochloride, which is generally used, diallylamine organic acid salt is weak in intramolecular polarization, and therefore has lower radical polymerization reactivity and tends to generate residual monomers than hydrochloride. Therefore, it is necessary to add a copolymerization monomer in order to improve the reaction rate. However, it is preferable to add it divided into a plurality of times. Since the copolymerization monomer is more reactive than the diallylamine organic acid salt, when added at once, a homopolymer of the copolymerization monomer is formed. Therefore, it is not consumed for copolymerization with diallylamine organic acid salt, and diallylamine organic acid salt remains. Therefore, it is desirable to add the copolymerization monomer in a plurality of times according to the reaction of the diallylamine organic acid salt to advance the reaction of the diallylamine organic acid salt.

General radical generators such as persulfates, peroxides, and azo salts can be used as reaction initiators for radical polymerization, but persulfates are added in large quantities because they generate sulfate ions after the reaction. Is not desirable. In addition, since the peroxide contains a product having an odor such as butanol in the polymer solution after the reaction, a treatment such as distillation may be required. In addition, there are many compounds with low water solubility, and the amount that can be added to the aqueous reaction system at one time is limited.
The azo salt has little influence on the odor except that nitrogen is generated in the reaction process, and is optimal for the reaction of diallylamine organic acid salt.
Examples of the initiator include potassium peroxodisulfate, ammonium peroxodisulfate, 2,2'-azobis (2-methylpropionamidine) dihydrochloride, 2,2'-azobis [N- (2-carboxyethyl)- 2-Methylpropionamidine] hydrate, 2,2′-azobis (1-imino-1-pyrrolidino-2-methylpropane) dihydrochloride, 2,2′-azobis [2- (2-imidazolin-2-yl) Propane] disulfate dihydrate and the like. Among them, those having a 10-hour half-temperature suitable for high temperature reaction of 60 ° C. or more are preferable.

  Since diallylamine organic acid salt is less reactive than acrylic acid compounds and styrene compounds, it is preferable to proceed the polymerization at a reaction temperature of 60 ° C. or higher, preferably 80 ° C. or higher. When the reaction is carried out at a low temperature of less than 60 ° C., particularly 40 ° C. or less, the reaction rate is remarkably inferior, and the reaction cannot be carried out sufficiently. The reason for this is that the reaction of diallylamine during radical polymerization involves both a chain termination reaction due to elimination of hydrogen as an allyl compound and a cyclization reaction specific to diallyl compounds, and the higher the temperature, the more intense the molecular motion. Therefore, it is presumed that the cyclization reaction proceeds predominately, the termination reaction hardly occurs, and the polymerization reaction easily proceeds.

As a reaction initiator suitable for such a high temperature reaction, those having a 10-hour half-life temperature of 60 ° C. or more are preferable. For example, potassium peroxodisulfate, ammonium peroxodisulfate, 2,2′-azobis [N- (2 -Carboxyethyl) -2-methylpropionamidine] hydrate, 2,2'-azobis [2- (2-imidazolin-2-yl) propane]. Some of these reaction initiators may be halogen salts, but if they contain halogen ions, it is better not to contain them.
The addition amount of the reaction initiator is preferably 10 mol% or less, more preferably 5 mol% or less, relative to the number of moles of monomers.

For the reaction rate of diallylamine, the cationic polymer produced by polymerization is adjusted to pH 3 with sulfuric acid, the amount of polymerized is calculated from the reaction equivalent with PVSK (polyvinyl potassium sulfate) by colloid titration, and the amount of residual diallylamine is calculated therefrom If you do.
Further, the amount of the unreacted copolymer monomer depends on the monomer species, but the monomer component extracted from the reaction system by hexane extraction or the like may be measured by general gas chromatography and quantitative evaluation may be performed. The molecular weight of the obtained polymer can be measured by GPC (gel permeation chromatography) using 0.5N acetic acid / 0.5N sodium acetate aqueous solution as an eluent, and converted into molecular weight using polyethylene glycol (PEG) as a standard substance. I can do it.

  The weight average molecular weight in terms of PEG of the copolymer of diallylamine organic acid salt varies greatly depending on each copolymer, but the weight molecular weight is preferably in the range of about 1,000 to 500,000, and more preferably in the range of about 5,000 to 250,000. As the copolymerization ratio, the molar ratio of diallylamine / copolymerization monomer = 1/9 to 9/1 is desirable from the viewpoint of polymerizability, and the ratio of 3/7 or more increases the cation concentration and exhibits an effect in a small amount. It is preferable because it is easy, and when there are more copolymer monomers than the above range, the reactivity of the copolymer monomers is too strong, making it difficult to produce a low molecular weight polymer. Moreover, the molecular weight of 7/3 or less is preferable in terms of molecular weight control because the molecular weight of the diallylamine organic acid salt can be increased due to the influence of the copolymerization monomer.

  The addition amount of the cationic polymer is preferably 1 to 40% by mass, more preferably 3 to 30% by mass, based on the entire pretreatment liquid. If the added amount is more than 40% by mass, the effect of improving the image quality is saturated and the liquid viscosity may be increased. If the added amount is less than 1% by mass, the effect of improving the image quality may be reduced. .

-Organic acid ammonium salt, organic acid amine salt-
It is preferable to add an organic acid ammonium salt or an organic acid amine salt to the pretreatment liquid for the purpose of assisting aggregation of the anion component in the ink. Organic acid ammonium salts include ammonium acetate, ammonium propionate, ammonium lactate, ammonium oxalate, ammonium tartrate, ammonium oxalate (diammonium oxalate), diammonium malonate, diammonium hydrogen citrate, triammonium citrate and L -Ammonium glutamate etc. are mentioned, Ammonium lactate is particularly preferable.
Examples of organic acid amine salts include lactate diethanolamine, lactate triethanolamine, lactate-1-amino-2,3-propanediol, lactate-1-methylamino-2,3-propanediol, lactate-2-amino- 2-methyl-1,3-propanediol, lactate-2-amino-2-ethyl-1,3-propanediol, acetic acid diethanolamine, acetic acid triethanolamine, acetic acid-1-amino-2,3-propanediol, acetic acid -1-methylamino-2,3-propanediol, acetate-2-amino-2-methyl-1,3-propanediol, acetate-2-amino-2-ethyl-1,3-propanediol, diethanolamine propionate , Triethanolamine propionate, 1-amino-2,3-propanediol propionate, propionate Acid-1-methylamino-2,3-propanediol, propionate-2-amino-2-methyl-1,3-propanediol, propionate-2-amino-2-ethyl-1,3-propanediol Etc.
The addition amount of the organic acid ammonium salt or the organic acid amine salt is preferably 1 to 40% by mass, more preferably 3 to 30% by mass, based on the entire pretreatment liquid. If the addition amount is more than 40% by mass, the image quality improvement effect may be saturated and the liquid viscosity may be increased. If the addition amount is less than 1% by mass, the image quality improvement effect may be reduced.

―Water-soluble organic solvent (wetting agent) ―
Water-soluble organic solvents (wetting agents) used in the pretreatment liquid include polyhydric alcohols, polyhydric alcohol alkyl ethers, polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds. Examples include compounds, propylene carbonate, and ethylene carbonate.
The water-soluble organic solvent (wetting agent) maintains the fluidity of the pretreatment liquid because the water-soluble organic solvent (wetting agent) retains a large amount of water even when the pretreatment liquid is left open. It has a function. In addition, when a water-soluble organic solvent (wetting agent) having a high equilibrium water content is used as the water-soluble organic solvent, even when the water in the pretreatment liquid evaporates and reaches an equilibrium state, an extreme increase in viscosity can be suppressed.

The water-soluble organic solvent (wetting agent) having a high equilibrium moisture content is a water-soluble organic solvent (wetting) having an equilibrium moisture content of 30% by mass or more, preferably 40% by mass or more in an environment at a temperature of 23 ° C. and a humidity of 80% Agent). Equilibrium water content means that a mixture of water-soluble organic solvent and water is opened to air at a constant temperature and humidity, and the evaporation of water in the solution and the absorption of water in the ink into the ink are in an equilibrium state. Says the amount of water when it becomes. Specifically, the equilibrium water content is determined by using a saturated aqueous solution of potassium chloride, keeping the temperature and humidity in the desiccator at 23 ± 1 ° C. and 80 ± 3%, and weighing 1 g of each water-soluble organic solvent in the desiccator. The petri dish can be stored for a period until the mass change disappears, and can be obtained by the following formula.

  Suitable water-soluble organic solvents (wetting agents) include polyhydric alcohols having an equilibrium water content of 30% by mass or more in an environment at a temperature of 23 ° C. and a humidity of 80%. Specific examples thereof include 1,2,3-butanetriol (bp 175 ° C./33 hPa, 38 mass%), 1,2,4-butane triol (bp 190 to 191 ° C./24 hPa, 41 mass%), glycerin (bp 290 ° C. 49 mass%), diglycerin (bp 270 ° C./20 hPa, 38 mass%), triethylene glycol (bp 285 ° C., 39 mass%), tetraethylene glycol (bp 324 to 330 ° C., 37 mass%), diethylene glycol (bp 245 ° C., 43 mass%), 1,3-butanediol (bp 203 to 204 ° C., 35 mass%) and the like. Of these, glycerin and 1,3-butanediol are particularly preferably used for reasons such as lowering the viscosity when water is contained, and keeping the pigment dispersion stable without aggregation. When the water-soluble organic solvent (wetting agent) is used in an amount of 50% by mass or more based on the total amount of the water-soluble organic solvent (wetting agent), it is preferable because it is excellent in securing ejection stability and preventing waste ink sticking in an ink ejection apparatus maintenance device.

In addition to the water-soluble organic solvent (wetting agent), a water-soluble organic solvent (wetting agent) having an equilibrium water content of less than 30% by mass at 23 ° C. and 80% may be used as necessary. Examples of such water-soluble organic solvents (wetting agents) include the following.
Examples of polyhydric alcohols include dipropylene glycol (bp 232 ° C.), 1,5-pentanediol (bp 242 ° C.), 3-methyl-1,3-butane diol (bp 203 ° C.), propylene glycol (bp 187 ° C.), 2-methyl-2,4-pentanediol (bp 197 ° C.), ethylene glycol (bp 196 to 198 ° C.), tripropylene glycol (bp 267 ° C.), hexylene glycol (bp 197 ° C.), polyethylene glycol (viscous liquid to solid), Polypropylene glycol (bp 187 ° C), 1,6-hexanediol (bp253-260 ° C), 2-ethyl-1,3-hexanediol (bp243 ° C), 1,2,6-hexanetriol (bp178 ° C), trimethylol Ethane (solid, mp 199-201 ° C) Trimethylolpropane (solid, MP61 ° C.), and the like.

Examples of polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether (bp 135 ° C.), ethylene glycol monobutyl ether (bp 171 ° C.), diethylene glycol monomethyl ether (bp 194 ° C.), diethylene glycol monoethyl ether (bp 197 ° C.), diethylene glycol monobutyl ether (Bp 231 ° C.), ethylene glycol mono-2-ethylhexyl ether (bp 229 ° C.), propylene glycol monoethyl ether (bp 132 ° C.) and the like.
Examples of polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether (bp 237 ° C.) and ethylene glycol monobenzyl ether.

Examples of the nitrogen-containing heterocyclic compound include 2-pyrrolidone (bp 250 ° C., mp 25.5 ° C., 47-48 mass%), N-methyl-2-pyrrolidone (bp 202 ° C.), 1,3-dimethyl-2-imidazo Examples include lysinone (bp 226 ° C.), ε-caprolactam (bp 270 ° C.), γ-butyrolactone (bp 204 to 205 ° C.), and the like.
Examples of amides include formamide (bp 210 ° C.), N-methylformamide (bp 199 to 201 ° C.), N, N-dimethylformamide (bp 153 ° C.), N, N-diethylformamide (bp 176 to 177 ° C.) and the like. It is done.
Examples of amines include monoethanolamine (bp 170 ° C), diethanolamine (bp268 ° C), triethanolamine (bp360 ° C), N, N-dimethylmonoethanolamine (bp139 ° C), N-methyldiethanolamine (bp243 ° C). N-methylethanolamine (bp 159 ° C), N-phenylethanolamine (bp 282 to 287 ° C), 3-aminopropyldiethylamine (bp 169 ° C) and the like.
Examples of sulfur-containing compounds include dimethyl sulfoxide (bp 139 ° C.), sulfolane (bp 285 ° C.), thiodiglycol (bp 282 ° C.), and the like.

Other humectants are preferably sugars.
Examples of the saccharide include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides), polysaccharides, and the like. Specific examples include glucose, mannose, fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose, lactose, sucrose, trehalose, maltotriose, and the like. Here, the polysaccharide means a saccharide in a broad sense, and is used to include a substance that exists widely in nature such as α-cyclodextrin and cellulose. The derivatives of these saccharides are represented by the reducing sugars of the saccharides described above {for example, sugar alcohol [general formula: HOCH ₂ (CHOH) nCH ₂ OH (where n represents an integer of 2 to 5)). ], Oxidized sugars (for example, aldonic acid, uronic acid, etc.), amino acids, thioic acids and the like. Among these, sugar alcohols are preferable, and specific examples include maltitol and sorbit.

  The content of the water-soluble organic solvent agent (wetting agent) in the pretreatment liquid is not particularly limited, but is usually 10 to 80% by mass, preferably 15 to 60% by mass. When the amount is more than 80% by mass, depending on the type of the water-soluble organic solvent (wetting agent), there is a possibility that the recording medium after the pretreatment may be dried. Moisture evaporation may occur and the composition of the pretreatment liquid may change significantly.

-Foam suppressant-
The antifoaming agent is used to suppress foaming of the pretreatment liquid. Here, foaming means that the liquid becomes a thin film and encloses air. The generation of the bubbles involves characteristics such as the surface tension and viscosity of the pretreatment liquid. That is, a liquid having a high surface tension such as water is difficult to foam because a force for reducing the surface area of the liquid as much as possible works. On the other hand, a high-viscosity and high-permeability pretreatment liquid is easy to foam because of its low surface tension, and it is easy to maintain foam generated by the viscosity of the solution and to prevent defoaming.
Usually, the foam suppressor destroys the foam by locally lowering the surface tension of the foam film to destroy the foam, or by interspersing the foam suppressor with a foam suppressor insoluble in the foam liquid. When a fluorosurfactant with a very strong action to reduce the surface tension is used in the pretreatment liquid, the surface tension of the foam film cannot be reduced locally even if the foam suppressor by the former mechanism is used. Therefore, it is not usually used. For this reason, an antifoaming agent that is insoluble in the latter foaming liquid is used.

On the other hand, the antifoaming agent represented by the following general formula is not as strong as the fluorosurfactant in reducing the surface tension, but is highly compatible with the fluorosurfactant. For this reason, when the foam is efficiently incorporated into the foam film, the surface of the foam film is locally unbalanced due to the difference in surface tension between the fluorosurfactant and the foam suppressor, and the foam is destroyed. Conceivable.
_{^{HOR 1 R 3 C- (CH 2}} ) n-CR 2 R 4 OH
In the above formula, R ¹ and R ² are independently alkyl groups having 3 to 6 carbon atoms, R ³ and R ⁴ are independently alkyl groups having 1 to 2 carbon atoms, and n is 1 to 1 It is an integer of 6.
Preferred foam suppressors represented by the general formula are 2,4,7,9-tetramethyldecane-4,7-diol and 2,5,8,11-tetramethyldodecane-5,8-diol. 2,5,8,11-tetramethyldodecane-5,8-diol is particularly preferable because of its high foam-suppressing effect and high compatibility with the pretreatment liquid.
The content of the foam suppressor in the pretreatment liquid is preferably 0.01 to 10% by mass, and more preferably 0.02 to 5% by mass. If the content is less than 0.01% by mass, the antifoaming effect may not be obtained. If the content exceeds 10% by mass, the antifoaming effect reaches its peak, and the solution does not dissolve in the pretreatment liquid and becomes nonuniform Physical properties may be adversely affected.

―Surfactant―
The pretreatment liquid improves the wettability of the surface of the recording medium, improves the image density, saturation and white spot of the image formed product, and improves the smear fixability by quickly penetrating the vehicle in the ink. Therefore, a surfactant can be used. In this case, it is preferable to adjust the static surface tension of the pretreatment liquid to 30 mN / m or less with a surfactant.
As the surfactant, nonionic surfactants, anionic surfactants, betaine surfactants, silicone surfactants, fluorine surfactants are preferably used, and in particular, the following fluorine surfactants Those selected from the agents are preferred. These surfactants may be used alone or in combination of two or more.

"Fluorosurfactant"
As the fluorine-based surfactant, those having 2 to 16 carbon atoms substituted with fluorine are preferable, and those having 4 to 16 carbon atoms are more preferable. If the number of carbon atoms substituted with fluorine is less than 2, the effect of fluorine may not be obtained, and if it exceeds 16, problems such as storage stability may occur.
Examples of fluorosurfactants include perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylic acid compounds, perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and perfluoroalkyl ether groups in the side chain. And polyoxyalkylene ether polymer compounds.
Particularly preferred are perfluoroalkylethylene oxide adducts and polyoxyethylene both-end alkyl ethers having one or both perfluoroalkyl groups.

  From the viewpoint of solubility in ink, the fluorosurfactant preferably has a Griffin HLB value of 10 to 16. Specific examples thereof include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Fullrad FC-93 , FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431, FC-4430 (all manufactured by Sumitomo 3M); Megafac F-470, F-1405 F-474 (all manufactured by Dainippon Ink & Chemicals, Inc.); Zonyl FS-300, FSN, FSN-100, FSO (all manufactured by DuPont); F-top EF-351, EF-352, EF-801, EF-802 (both manufactured by Gemco) can be used. Among these, Zonyl FS-300, FSN, FSN-100, and FSO-100 (all manufactured by DuPont), which are favorable in terms of reliability and color development, are particularly suitable. These commercial products are a mixture of compounds having several kinds of molecular weights, but there is no problem in the effect of the present invention.

  0.01-10 mass% is preferable and, as for content of the fluorochemical surfactant in a pre-processing liquid, 0.03-5 mass% is more preferable. If the content is less than 0.01% by mass, an effect of improving the color developability at a level that can be felt visually cannot be obtained, and the effect of improving the smear fixing property by rapidly penetrating the vehicle in the ink may not be observed. On the other hand, if it exceeds 10% by mass, the above-mentioned effect will reach its peak, and it may not be dissolved in the pretreatment liquid, resulting in non-uniformity and adversely affecting liquid properties.

―Other ingredients―
If necessary, the pretreatment liquid may contain a penetrant, a preservative used in inks described later, a rust preventive, and the like as necessary.
The penetrant preferably contains at least one of a non-wetting agent polyol compound or glycol ether compound having 8 to 11 carbon atoms. These preferably have a solubility of 0.2 to 5.0% by mass in water at 25 ° C., among which 2-ethyl-1,3-hexanediol [solubility: 4.2% (25 ° C.)], 2,2,4-trimethyl-1,3-pentanediol [solubility: 2.0% (25 ° C.)] is particularly preferred.
Examples of other non-wetting agent polyol compounds include 2-ethyl-2-methyl-1,3-propanediol, 3,3-dimethyl-1,2-butanediol, and 2,2-diethyl-1,3. -Propanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol, 2,5-dimethyl-2,5-hexanediol, 5-hexene-1 , 2-diol and the like.

In addition to the above, penetrants that can be dissolved in the ink and adjusted to the desired physical properties can be appropriately used depending on the purpose. Examples thereof include alkyls and aryls of polyhydric alcohols such as diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, and tetraethylene glycol chlorophenyl ether. And ethers, lower alcohols such as ethanol, and the like.
The content of the penetrant in the pretreatment liquid is preferably 0.1 to 5.0% by mass. When the content is less than 0.1% by mass, the effect of penetrating the ink may not appear. When the content exceeds 5.0% by mass, the solubility in the solvent is low, so the permeability is improved by separating from the solvent. May cause the effect to be saturated.

<Inkjet ink>
The inkjet ink used for image formation in combination with the pretreatment liquid of the present invention is not particularly limited, but usually contains a water-dispersible colorant, a water-soluble organic solvent, a surfactant, a penetrating agent, and water. In addition, other components may be added as necessary-water-dispersible colorant-
As the water-dispersible colorant, a pigment is mainly used from the viewpoint of weather resistance. However, a dye may be used in combination within the range in which the weather resistance is not deteriorated for color tone adjustment.
There is no restriction | limiting in particular as a pigment, According to the objective, it can select suitably, For example, the inorganic pigment, organic pigment, etc. for black or color are mentioned. These may be used alone or in combination of two or more.

Inorganic pigments include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow, as well as carbon produced by known methods such as the contact method, furnace method, and thermal method. Black can be used.
Organic pigments include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments), polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, Indigo pigments, thioindigo pigments, isoindolinone pigments, quinofullerone pigments, etc.), dye chelates (eg, basic dye type chelates, acidic dye type chelates), nitro pigments, nitroso pigments, aniline black, and the like can be used.
Of these pigments, those having good affinity with water are particularly preferably used.

  Among the above, specific examples of more preferable pigments include, for black, carbon blacks such as furnace black, lamp black, acetylene black, channel black (CI pigment black 7), copper, iron (CI) And pigments such as pigment black 11), metal oxides such as titanium oxide, and organic pigments such as aniline black (CI pigment black 1).

  For color, C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104 , 408, 109, 110, 117, 120, 128, 138, 150, 151, 153, 183, C.I. I. Pigment orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48: 2, 48: 2 [Permanent Red 2B (Ca)], 48: 3, 48: 4, 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Bengara), 104, 105, 106, 108 ( Cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 185, 190, 193, 209, 219, C.I. I. Pigment violet 1 (rhodamine lake), 3, 5: 1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15, 15: 1, 15: 2, 15: 3 (phthalocyanine blue), 16, 17: 1, 56, 60, 63, C.I. I. Pigment green 1, 4, 7, 8, 10, 17, 18, 36, and the like.

The following first to third modes are particularly preferable when the colorant is a pigment. Moreover, in the case of the 2nd form or the 3rd form, it is preferable that the water dispersible resin mentioned later is included.
(1) In the first embodiment, the water-dispersible colorant contains a polymer emulsion (an aqueous dispersion of polymer particles containing a colorant) in which polymer particles contain a colorant that is insoluble or hardly soluble in water.
(2) In the second embodiment, the water-dispersible colorant has at least one hydrophilic group on the surface and exhibits water dispersibility in the absence of the dispersant (hereinafter referred to as “self-dispersible pigment”). In some cases).
(3) In the third embodiment, the water-dispersible colorant contains a pigment dispersed with an anionic dispersant or a nonionic dispersant.

  As the water-dispersible colorant of the first form, it is preferable to use a polymer emulsion in which a pigment is contained in polymer fine particles in addition to the pigment. The polymer emulsion in which the pigment is contained in the polymer fine particles is one in which the pigment is encapsulated in the polymer fine particles, or the pigment is adsorbed on the surface of the polymer fine particles. In this case, it is not necessary for all the pigments to be encapsulated or adsorbed, and the pigments may be dispersed in the emulsion as long as the effects of the present invention are not impaired. Examples of the polymer that forms the polymer emulsion (polymer in the polymer fine particles) include vinyl polymers, polyester polymers, polyurethane polymers, and the like. Particularly preferred are vinyl polymers and polyester polymers, and JP-A 2000-53897. And the polymers disclosed in JP 2001-139849 A can be used.

The self-dispersing pigment of the second form is a surface modified so that at least one hydrophilic group is bonded to the surface of the pigment directly or via another atomic group. In the surface modification, a specific functional group (functional group such as a sulfonic acid group or a carboxyl group) is chemically bonded to the surface of the pigment, or at least one of hypohalous acid or a salt thereof is used. A method such as wet oxidation is used. Among these, a form in which a carboxyl group is bonded to the surface of the pigment and dispersed in water is particularly preferable. Since the pigment is thus surface-modified and the carboxyl group is bonded, the dispersion stability is improved, high-quality print quality is obtained, and the water resistance of the recording medium after printing is further improved.
In addition, since the ink containing the self-dispersing pigment of the second form is excellent in redispersibility after drying, clogging also occurs when printing in the ink near the inkjet head nozzles is evaporated for a long period of time and printing is suspended. Good printing can be easily performed with a simple cleaning operation without causing it.
The volume average particle diameter (D50) of the self-dispersing pigment is preferably 0.01 to 0.16 μm in the ink.

For example, as the self-dispersing carbon black, those having ionicity are preferable, and those having an anionic charge are preferable.
Examples of the anionic hydrophilic _{group, -COOM, -SO 3 M, -PO} 3 HM, -PO 3 M 2, -SO 2 NH 2, -SO 2 NHCOR ( although, M is an alkali metal, ammonium or organic R represents ammonium, and R represents an alkyl group having 1 to 12 carbon atoms, a phenyl group which may have a substituent, or a naphthyl group which may have a substituent. Among these, those in which —COOM and —SO ₃ M are bonded to the surface of the color pigment are preferable.
Examples of the alkali metal “M” include lithium, sodium, and potassium. Examples of the organic ammonium include mono to trimethyl ammonium, mono to triethyl ammonium, and mono to trimethanol ammonium.

As a method for obtaining an anionically charged color pigment, for example, -COONa is introduced into the surface of the color pigment, for example, a method in which the color pigment is oxidized with sodium hypochlorite, a method by sulfonation, or a reaction with a diazonium salt. The method of letting it be mentioned.
The anionic hydrophilic group may be bonded to the surface of carbon black via another atomic group. Examples of other atomic groups include an alkyl group having 1 to 12 carbon atoms, a phenyl group which may have a substituent, or a naphthyl group which may have a substituent. Specific examples _thereof, -C ₂ H 4 COOM (provided that, M represents an alkali metal or quaternary ammonium), - PhSO ₃ M (however, Ph is a phenyl group .M include alkali Metal or quaternary ammonium).

Examples of the water-dispersible colorant of the third form include those obtained by dispersing a pigment with an anionic dispersant or a nonionic dispersant.
Examples of anionic dispersants include polyoxyethylene alkyl ether acetates, alkylbenzene sulfonates (NH ₄ , Na, Ca), alkyl diphenyl ether disulfonates (NH ₄ , Na, Ca), Na dialkyl succinate sulfonates Salt, naphthalenesulfonic acid formalin condensate Na salt, polyoxyethylene polycyclic phenyl ether sulfate ester salt (NH ₄ , Na), laurate, polyoxyethylene alkyl ether sulfate salt, oleate and the like. Among them, particularly useful specific examples include dioctyl sulfosuccinic acid Na salt and polyoxyethylene styrene phenyl ether sulfonic acid NH ₄ salt.

  As the nonionic dispersant, a dispersant having an HLB value of 10 to 20 is preferable. Examples thereof include polyoxyethylene alkyl ether, polyoxyalkylene alkyl ether, polyoxyethylene polycyclic phenyl ether, sorbitan fatty acid ester, and polyoxyethylene sorbitan. Examples include fatty acid esters, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl amines, polyoxyethylene alkyl amides, and acetylene glycols. Among these, particularly useful specific examples include polyoxyethylene lauryl ether, polyoxyethylene-β-naphthyl ether, polyoxyethylene sorbitan monooleate, and polyoxyethylene styrene phenyl ether.

  The pigment dispersion is obtained by dissolving the pigment dispersant in an aqueous medium, adding the organic pigment or inorganic pigment and thoroughly moistening the mixture, then stirring at high speed with a homogenizer, and using a ball such as a bead mill or a ball mill. And a kneading disperser using a shearing force such as a roll mill, an ultrasonic disperser, and the like. However, after such a kneading and dispersing step, coarse particles are often contained, which may cause clogging of the ink jet nozzle and the supply path. Therefore, particles having a particle diameter of 1 μm or more using a filter or a centrifuge. Need to be removed.

The dispersant is preferably used in a ratio range of 1 to 100% by mass with respect to the pigment, and more preferably 10 to 50% by mass. If the amount of the dispersant is small, the pigment cannot be sufficiently miniaturized. If the amount of the dispersant is too large, excess components that are not adsorbed on the pigment affect the ink physical properties. It will cause deterioration.
Furthermore, a dispersion-stabilized aqueous pigment dispersion can be obtained by using a water-soluble polymer compound having an average molecular weight of 30000 or less in combination.

Examples of the water-soluble polymer compound include a water-soluble styrene-acrylic resin having a molecular weight of 30000 or less, a water-soluble acrylic resin, a water-soluble polyurethane, a water-soluble polyester, a water-soluble styrene-maleic acid copolymer, and a water-soluble α-olefin-maleic acid. A copolymer is preferred. Particularly preferred are water-soluble polyurethanes, water-soluble polyesters and water-soluble α-olefin-maleic acid copolymers (6 to 22 carbon atoms of the side chain alkyl group derived from α-olefin, number average molecular weight of about 30 to 100). The acid value is preferably 100 to 400 (mgKOH / g), and the weight average molecular weight is preferably 5000 to 20000. If the acid value is less than 100, the solubility of the alkaline solution is poor. On the other hand, when the acid value exceeds 400, the viscosity of the pigment dispersion is increased, and it is likely that the discharge is easily deteriorated or the dispersion stability of the pigment dispersion is likely to be lowered. When the weight average molecular weight is less than 5000, the dispersion stability of the pigment dispersion is lowered, and when it exceeds 20000, the solubility of the alkaline solution is inferior and the viscosity is increased.
The amount of the water-soluble polymer compound used is preferably 1 to 100% by mass (in terms of solid content), more preferably 5 to 50% by mass, based on the pigment. If it is less than 1% by mass, there is no effect of stabilizing the dispersion. On the other hand, if it exceeds 100% by mass, the ink viscosity becomes high and the ejection from the nozzle tends to deteriorate. Also, since the dispersion stabilizing effect is saturated, it is uneconomical to add a lot of waste.

The volume average particle diameter (D50) of the pigment fine particles (coloring material) is preferably 150 nm or less, more preferably 100 nm or less in the ink. When the volume average particle diameter (D50) exceeds 150 nm, the ejection stability rapidly decreases, and nozzle clogging and ink bending are likely to occur. In addition, when the volume average particle diameter (D50) is 100 nm or less, the ejection stability is improved and the saturation of the image is also improved.
The pigment content in the ink is preferably about 1 to 15% by mass, more preferably about 2 to 12% by mass.
Further, there is no particular problem even if the water-dispersible colorant of the first form and the self-dispersible pigment of the second form or the water-dispersible colorant of the third form are used in combination.
The content of the colorant in the ink is preferably 2 to 15% by mass and more preferably 3 to 12% by mass in terms of solid content. If the content is less than 2% by mass, the color developability and the image density of the ink may be lowered, and if it exceeds 15% by mass, the ink may be thickened and the dischargeability may be deteriorated. Absent.

―Water-soluble organic solvent (wetting agent) ―
As the water-soluble organic solvent (wetting agent) to be blended in the ink, the same water-soluble organic solvent (wetting agent) as in the case of the pretreatment liquid is preferably used.
The mass ratio of the water-dispersible colorant and the water-soluble organic solvent (wetting agent) in the ink affects the ink ejection stability from the head. For example, if the amount of the water-soluble organic solvent (wetting agent) is small even though the water-dispersible colorant has a high solid content, water evaporation near the ink meniscus of the nozzle may progress and cause ejection failure. The content of the water-soluble organic solvent (wetting agent) in the ink is preferably 20 to 50% by mass, and more preferably 20 to 45% by mass. If the content is less than 20% by mass, the ejection stability may be lowered, or the waste ink may be fixed by the maintenance device of the ink jet recording apparatus. On the other hand, if it exceeds 50% by mass, the drying property on paper is inferior and the character quality on plain paper may be lowered.

―Surfactant―
As the surfactant to be blended in the ink, those having a low surface tension, low penetrability and high leveling property are preferable because the dispersion stability is not impaired by the combination of the colorant and the water-soluble organic solvent (wetting agent). At least one selected from a surfactant based on a surfactant, a nonionic surfactant, a silicone surfactant, and a fluorine surfactant is preferred. Among these, silicone surfactants and fluorine surfactants are particularly preferable. These surfactants may be used alone or in combination of two or more.
As such a surfactant, the same one as in the case of the pretreatment liquid is preferably used.
The content of the surfactant in the ink is preferably 0.01 to 3.0% by mass, and more preferably 0.5 to 2% by mass. When the content is less than 0.01% by mass, the effect of adding a surfactant may not appear. When the content exceeds 3.0% by mass, the permeability to a recording medium becomes higher than necessary, and the image density May be reduced or show through.

―Penetration agent―
As the penetrating agent to be blended in the ink, the same one as in the case of the pretreatment liquid is preferably used. The content of the penetrant in the ink is preferably 0.1 to 4.0% by mass. If the content is less than 0.1% by mass, quick-drying may not be obtained and a blurred image may be obtained. If the content exceeds 4.0% by mass, the dispersion stability of the colorant is impaired, and the nozzle is easily clogged. In some cases, the permeability to the recording medium is unnecessarily high, and the image density is lowered or the back-through occurs.

―Water-dispersible resin―
Examples of water-dispersible resins include condensation-type synthetic resins, addition-type synthetic resins, natural polymer compounds that have excellent film-forming properties (image-forming properties) and high water repellency, high water resistance, and high weather resistance. It is done. These are useful for image recording with high water resistance and high image density (high color development).
Examples of the condensed synthetic resin include polyester resin, polyurethane resin, polyepoxy resin, polyamide resin, polyether resin, poly (meth) acrylic resin, acrylic-silicone resin, and fluorine-based resin.
Examples of the addition type synthetic resin include polyolefin resins, polystyrene resins, polyvinyl alcohol resins, polyvinyl ester resins, polyacrylic acid resins, unsaturated carboxylic acid resins, and the like.
Examples of the natural polymer compound include celluloses, rosins, and natural rubber.
Among these, polyurethane resin fine particles, acrylic-silicone resin fine particles, and fluorine-based resin fine particles are particularly preferable. Two or more kinds of the water dispersible resins may be used in combination.

The water dispersible resin may be used as a homopolymer or a copolymerized composite resin, and any of a single phase structure type, a core shell type, and a power feed type emulsion can be used.
As the water-dispersible resin, a resin itself having a hydrophilic group and having a self-dispersibility, or a resin itself having no dispersibility and imparted with a surfactant or a resin having a hydrophilic group can be used. Among these, an emulsion of resin particles obtained by emulsion polymerization or suspension polymerization of an ionomer of a polyester resin or polyurethane resin or an unsaturated monomer is optimal.
In the case of emulsion polymerization, an emulsion of a water-dispersible resin can be easily obtained by reacting in water to which an unsaturated monomer, a polymerization initiator, a surfactant, a chain transfer agent, a chelating agent, a pH adjusting agent, etc. are added. Therefore, it is easy to change the resin configuration and to easily obtain the desired properties.

  Examples of unsaturated monomers include unsaturated carboxylic acids, monofunctional or polyfunctional (meth) acrylic acid ester monomers, (meth) acrylic acid amide monomers, and aromatic vinyl monomers. , Vinyl cyano compound monomers, vinyl monomers, allyl compound monomers, olefin monomers, diene monomers, oligomers having unsaturated carbon, etc., alone or in combination Can do. By combining these monomers, the properties can be flexibly modified, and the properties of the resin can be modified by performing a polymerization reaction or a graft reaction using an oligomer type polymerization initiator.

The water-dispersible resin has a strong alkalinity and strong acidity, which causes molecular breakage such as dispersion breakage and hydrolysis. Therefore, the pH is preferably 4 to 12, particularly from the viewpoint of miscibility with the water-dispersible colorant. The pH is more preferably 6-11, and even more preferably 7-9.
The average particle size (D50) of the water-dispersible resin is related to the viscosity of the dispersion, and for the same composition, the viscosity at the same solid content increases as the particle size decreases. The average particle diameter (D50) of the water-dispersible resin is preferably 50 nm or more so that the viscosity does not become excessively high when converted into an ink. Further, when the particle size is several tens of μm, it becomes larger than the nozzle opening of the ink jet head and cannot be used. If particles having a large particle diameter are present in the ink even if they are smaller than the nozzle opening, the discharge property is deteriorated. Therefore, the average particle diameter (D50) is preferably 200 nm or less, and more preferably 150 nm or less, in order not to inhibit the ink discharge properties.
The water-dispersible resin has a function of fixing the water-dispersible colorant on the paper surface, and is preferably formed into a film at room temperature to improve the fixability of the color material. Therefore, the minimum film-forming temperature (MFT) of the water-dispersible resin is preferably 30 ° C. or lower. Further, when the glass transition temperature of the water dispersible resin is -40 ° C. or lower, the resin film becomes more viscous and the printed matter is tacked. Therefore, the water dispersible resin has a glass transition temperature of −30 ° C. or higher. It is preferable.

  The content of the water-dispersible resin in the ink is preferably 1 to 15% by mass and more preferably 2 to 7% by mass in terms of solid content. The solid content in the ink can be measured, for example, by a method of separating only the water-dispersible colorant and the water-dispersible resin component from the ink. When a pigment is used as the water dispersible colorant, the ratio of the colorant to the water dispersible resin can be measured by evaluating the mass reduction rate by thermal mass spectrometry. In addition, when the molecular structure of the water-dispersible colorant is clear, the solid content of the colorant can be quantified using NMR for pigments and dyes, and the inorganic pigment contained in the heavy metal atom, molecular skeleton, With a metal-containing organic pigment and a metal-containing dye, the solid content of the colorant can be quantified using fluorescent X-ray analysis.

―Other ingredients―
There is no restriction | limiting in particular as another component, It can select suitably as needed, For example, pH adjuster, antiseptic / antifungal agent, chelating reagent, rust preventive agent, antioxidant, ultraviolet absorber, oxygen absorber , Light stabilizers, and the like.

The pH adjuster is not particularly limited as long as it can adjust the pH to 7 to 11 without adversely affecting the prepared ink, and can be appropriately selected according to the purpose. When the pH is less than 7 or more than 11, the amount of the ink jet head or the ink supply unit that melts out is large, and problems such as ink degeneration, leakage, and ejection failure may occur.
Examples of pH adjusting agents include alcohol amines, alkali metal hydroxides, ammonium hydroxides, phosphonium hydroxides, alkali metal carbonates, and the like.
Examples of alcohol amines include diethanolamine, triethanolamine, 2-amino-2-ethyl-1,3-propanediol, and the like.
Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide.
Examples of the ammonium hydroxide include ammonium hydroxide and quaternary ammonium hydroxide.
Examples of the phosphonium hydroxide include quaternary phosphonium hydroxide.
Examples of the alkali metal carbonate include lithium carbonate, sodium carbonate, and potassium carbonate.

Examples of the antiseptic / antifungal agent include sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, sodium pentachlorophenol, 1,2-benzoisothiazolin-3-one sodium compound, etc. Is mentioned.
Examples of the chelating reagent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uramil diacetate, and the like.
Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite, 1,2,3-benzotriazole, and the like.
Examples of the antioxidant include phenolic antioxidants (including hindered phenolic antioxidants), amine-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, and the like.
Examples of the ultraviolet absorber include a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, a salicylate ultraviolet absorber, a cyanoacrylate ultraviolet absorber, and a nickel complex ultraviolet absorber.

―Inkjet ink manufacturing method―
The ink is prepared by dispersing or dissolving a water-dispersible colorant, a water-soluble organic solvent, a surfactant, a penetrating agent, water, and other components as necessary in an aqueous medium, and stirring and mixing as necessary. To manufacture. The stirring and mixing can be performed by, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, an ultrasonic disperser, or the like, and can be performed by a normal stirrer using a stirring blade, a magnetic stirrer, a high-speed disperser, or the like. .

-Physical properties of inkjet ink-
The physical properties of the ink are not particularly limited and can be appropriately selected according to the purpose.
The viscosity at 25 ° C. of the ink is preferably 5 to 20 mPa · s. By setting it to 5 mPa · s or more, the effect of improving the printing density and the character quality can be obtained. On the other hand, by suppressing to 20 mPa · s or less, dischargeability can be ensured. In addition, a viscosity can be measured at 25 degreeC, for example using a viscometer (RE-550L, the Toki Sangyo company make).
The static surface tension of the ink at 25 ° C. is preferably 20 to 35 mN / m, and more preferably 20 to 30 mN / m or less. If it is in the range of 20 to 35 mN / m, since the permeability is high, the effect of reducing bleeding is high, and the drying property on plain paper printing is good. Moreover, since it is easy to get wet with the pretreatment layer, the color development is good and the white spots are also improved. However, if it exceeds 35 mN / m, leveling of the ink hardly occurs on the recording material, and the drying time may be prolonged.
There is no restriction | limiting in particular in the color of an ink, According to the objective, it can select suitably, Yellow, magenta, cyan, black etc. are mentioned. When recording is performed with an ink set in which two or more of these color inks are used in combination, a multicolor image can be formed, and when recording is performed with an ink set in which all colors are used in combination, a full color image can be formed.

As an ink jet head, an ink droplet is formed by deforming a diaphragm that forms a wall surface of an ink flow path by using a piezoelectric element as pressure generating means for pressurizing the ink in the ink flow path, thereby changing the volume of the ink flow path. So-called piezo type (see Japanese Patent Application Laid-Open No. 2-51734), or so-called thermal type that generates bubbles by heating ink in an ink flow path using a heating resistor (Japanese Patent Application Laid-Open 61-59911), the diaphragm and the electrode forming the wall surface of the ink flow path are arranged to face each other, and the diaphragm is deformed by the electrostatic force generated between the vibration plate and the electrode, whereby the ink flow path Good for printers equipped with any inkjet head such as an electrostatic type that changes the internal volume and ejects ink droplets (see JP-A-6-71882) It can be used.
The ink can be used, for example, in a printer or the like having a function of heating the recording medium and ink at 50 to 200 ° C. at the time of printing or before and after printing to promote printing fixing.

<Recording media>
As the recording medium, plain paper having no coating layer is preferably used, and plain paper having a sizing degree of 10 S or more and an air permeability of 5 to 50 S generally used as a copy sheet is preferred.

<Image forming method>
An image forming method includes a pretreatment step in which a pretreatment liquid is applied to a recording medium, and an ink flight in which a stimulus is applied to the ink and the ink is ejected onto the recording medium to which the pretreatment liquid is applied to form an image. Process.
―Pretreatment process―
The pretreatment step is not particularly limited as long as a coating method for uniformly applying the pretreatment liquid to the surface of the recording medium is used. As the coating method, for example, blade coating method, gravure coating method, gravure offset coating method, bar coating method, roll coating method, knife coating method, air knife coating method, comma coating method, U comma coating method, AKKU coating method, Examples thereof include a smoothing coating method, a micro gravure coating method, a reverse roll coating method, a 4 to 5 roll coating method, a dip coating method, a curtain coating method, a slide coating method, and a die coating method.

The pretreatment step exhibits an effect whether it is performed on a recording medium whose surface is sufficiently dried or on a recording medium being dried. In addition, a drying process can be provided for the recording medium subjected to the pretreatment as necessary. In this case, the recording medium can be dried by a roll heater, a drum heater or hot air.
The wet adhesion amount of the pretreatment liquid to the recording medium is preferably in the range of 0.1 to 30.0 g / m ² , more preferably 0.2 to 10.0 g / m ² . When the adhesion amount is less than 0.1 g / m ² , there is almost no improvement in image quality (image density, saturation, color bleed, character bleeding and white spot), and when it exceeds 30.0 g / m ² , The texture of plain paper may be damaged or curl may occur.

―Ink flight process―
The ink flying step is a step of forming an image by applying a stimulus (energy) to the ink and causing the ink to fly to a recording medium coated with the pretreatment liquid. As a method for forming an image on a recording medium by flying ink, various known ink jet recording methods can be applied. Examples of such a method include an inkjet recording method in which a head is scanned, and an inkjet recording method in which image recording is performed on a single sheet of recording medium by using a lined head.
There is no particular limitation on the driving method of the recording head, which is an ink flying means, and a piezoelectric element actuator using PZT, a method of applying thermal energy, an on-demand type head using an actuator using electrostatic force, etc. should be used. It is also possible to record with a continuous injection type charge control type head. In the method of applying thermal energy, it is difficult to freely control the ejection of droplets, and there is a tendency for the image to vary widely depending on the type of recording media. By adding to the above, these problems are solved, and stable high image quality can be obtained regardless of the type of recording medium.

-apparatus-
An apparatus for forming an image with ink after applying a pretreatment liquid to a recording medium will be described with reference to FIG. FIG. 2 is a diagram illustrating an example of a recording apparatus that scans an inkjet recording head to form an image.
In the apparatus of FIG. 2, the recording medium 6 is sent out by a paper feed roller 7, and the pretreatment liquid 1 is uniformly and thinly applied to the recording medium 6 by the applying roller 4 and the counter roller 5. The pretreatment liquid 1 is pumped by the pumping roller 3 and is uniformly applied to the applying roller 4 by the film thickness control roller 2. The recording medium 6 to which the pretreatment liquid 1 is applied is sent to a recording scanning unit where the inkjet recording head 20 is provided. The length of the paper path from the end portion (A portion in FIG. 2) of the pretreatment liquid application operation to the recording scan start portion (B portion in FIG. 2) is set to be longer than the length of the recording medium 6 in the feeding direction. Therefore, when the recording medium 6 reaches the recording scan start portion, the application of the pretreatment liquid 1 can be completely completed. In this case, since the pretreatment liquid 1 can be applied before the inkjet recording head 20 starts scanning for printing and before the recording medium 6 is intermittently conveyed, the conveyance speed of the recording medium 6 is high. It can be applied continuously in a constant state, and uniform application without unevenness is possible. In the apparatus of FIG. 2, the recording medium 6 that requires preprocessing is supplied from the lower cassette, and the recording medium 17 that does not need to be preprocessed is supplied from the upper cassette. Therefore, it is convenient to provide a long recording medium conveyance path.

FIG. 3 shows an example of another recording apparatus of a type that scans an inkjet recording head to form an image. This is an example of a compact device configuration compared to the device of FIG.
The recording medium 17 is sent out by the paper feed roller 18, and the pretreatment liquid 1 is uniformly and thinly applied to the recording medium 17 by the applying roller 4 and the counter roller 5. The pretreatment liquid 1 is pumped by the pumping roller 3 and is uniformly applied to the applying roller 4 by the film thickness control roller 2. The recording medium 17 passes through a recording scanning portion of the inkjet recording head 20 while being applied with the pretreatment liquid 1, and is sent until the recording medium 17 completes the application of the pretreatment liquid 1. Is completed until the top of the recording medium 17 reaches the recording scan start position. Completion of application can be detected, for example, by providing a known recording medium detection means (not shown) near the outlet of the pretreatment liquid application apparatus. This detection means is not always necessary, and information on the length of the recording medium 17 is input to the controller in advance, and the rotation amount of the motor is controlled, so that the feed amount of the outer periphery of the conveyance roller of the recording medium 17 is changed to the recording medium. A system configuration corresponding to a length of 17 may be adopted.

  The recording medium 17 to which the pretreatment liquid 1 is applied is conveyed again to the recording scanning position before the pretreatment liquid 1 is dried and solidified. At this time, the scanning and timing of the ink jet recording head 20 are performed. And are conveyed intermittently. When the same path as the path sent when returning the recording medium 17 is returned, the rear end of the recording medium 17 enters back into the pretreatment liquid applying device, and uneven coating, dirt, recording media jam, etc. However, when the recording medium 17 is returned, the direction is switched by the recording medium guide 31. That is, when the recording medium 17 is reversely fed after the pretreatment liquid 1 is applied to the recording medium 17, the recording medium guide 31 is moved to the position of the dotted line in the figure by a known means such as a solenoid or a motor. . Thereby, since the recording medium 17 is conveyed to the position of the recording medium return guide 34, it is possible to prevent the recording medium 17 from being soiled or jammed.

  The pretreatment step is preferably performed continuously at a constant linear velocity of 10 to 1000 mm / s. Therefore, in this apparatus, when the recording medium 17 of a single sheet is used and the recording medium 17 of a certain sheet is used, after the process of applying the pretreatment liquid 1 to the recording medium 17 is completed for the single sheet, The process of recording an image by the inkjet recording method is started. In such an apparatus, since the pretreatment liquid application speed and the image recording speed do not coincide in most cases, the pretreatment liquid 1 is applied at the recording start portion and the recording end portion of the sheet. There is a difference in the time from when the image is recorded to when the image is recorded. Even if this difference becomes considerably large, it contains a large amount of a hydrophilic solvent having a boiling point higher than that of water and a low evaporation rate, so that the amount is balanced with the moisture in the air in the environment where the recording apparatus is used. In the pretreatment liquid 1 prepared at a close moisture ratio, water evaporation from the liquid is remarkably suppressed, so that the difference in image quality that occurs between the recording start portion and the recording end portion of the recording medium 17 of the single wafer is The level can be at least below the level that can be visually observed.

  As is apparent from the conveying process of the recording medium 17 in this apparatus, after the pretreatment liquid 1 is applied, the recording medium 17 to which the pretreatment liquid 1 is applied is provided with a roller, In many cases, it is necessary to transport the recording medium 17 by means such as a roller or a guide that contacts the recording medium 17. In such a case, if the pretreatment liquid 1 applied to the recording medium 17 is transferred to the conveying member of the recording medium 17, the conveying function is disturbed, dirt is accumulated, and the image quality is reduced. The problem that it falls is caused. In order to prevent this problem, measures such as making the guide into corrugated plates, rolling rollers into a spur shape, or using a water-repellent material on the surface of the roller are alleviated from the device side. Can do.

  However, it is desirable that the pretreatment liquid 1 applied to the recording medium 17 is absorbed by the recording medium 17 as quickly as possible and is in an apparently dry state. In order to achieve this object, it is effective to set the surface tension of the pretreatment liquid 1 to 30 mN / m or less so that the pretreatment liquid 1 quickly penetrates into the recording medium 17. “Dry solidification” after application of the pretreatment liquid does not mean that the pretreatment liquid 1 is absorbed into the recording medium 17 as described above and apparently becomes dry. This means that the liquid compound in the liquid evaporates and cannot be maintained in a liquid state and solidifies. By using the recording apparatus in which the pretreatment liquid application apparatus and the image recording apparatus are set as described above, the pretreatment liquid 1 is absorbed by the recording medium 17 and is apparently dry. However, inkjet recording can be performed in a state where the pretreatment liquid 1 is not solidified, and the image quality can be remarkably improved even if the amount of the pretreatment liquid 1 applied is extremely small.

  In order to control the operation of the apparatus shown in FIGS. 2 and 3, upon receiving a print command from a host machine such as a personal computer, the pretreatment liquid application / image forming apparatus performs head cleaning work and pretreatment liquid application work. Start at the same time and start recording when all preparations are complete. In this case, the transfer of image data may be for one scan, for a plurality of scans, or for one page. Head cleaning and ejection check operations are not always necessary. In addition, it is not necessary to perform head cleaning, ejection check operation and image data processing / image data transfer sequentially, but in parallel, such as pretreatment liquid application, head cleaning, ejection check operation and image data processing / image data transfer are started simultaneously. Can be processed. As described above, the pretreatment liquid application, the head cleaning, the ejection check operation and the image data processing / image data transfer are processed in parallel, so that the throughput of the print recording apparatus can be reduced even when the pretreatment liquid application work is performed. It is possible to record an image without dropping it.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated further more concretely, this invention is not limited at all by these Examples. In the examples, “%” is “mass%”.

Examples 1-14, Comparative Examples 1-3
<< Preparation of pretreatment liquid >>
(1) Preparation of cationic polymer <Preparation of diallylamine lactate-acrylamide copolymer>
Preparation Example A-0 for Diallylamine Lactate
In a 1 L three-necked separable flask equipped with a stirrer, a thermometer, and a reflux condenser, 288.3 g of 50% lactic acid and 356.3 g of ion-exchanged water were charged and stirred. While cooling to 60 ° C. or lower, 155.5 g of diallylamine was added dropwise to prepare a 37% diallylamine lactate aqueous solution.

Preparation Example A-1
In a 1 L four-necked separable flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube, 85.0 g of diallylamine lactate aqueous solution prepared in Preparation Example A-0, 60.3 g of 40% acrylamide aqueous solution, A 10% sodium methallylsulfonate aqueous solution (10.7 g), a 10% crewat # 300A aqueous solution (1.7 g), and ion-exchanged water (334.6 g) were charged, and the temperature was raised to 80 ° C. while introducing nitrogen gas while stirring. When the liquid temperature was stabilized, 1.5 g of a 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 85.0 g of diallylamine lactate aqueous solution prepared in Preparation Example A-0, 60.3 g of 40% acrylamide aqueous solution, and 10.7 g of 10% sodium methallylsulfonate aqueous solution were put into the flask, and the liquid temperature was 80 ° C. When stabilized, 1.5 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 60.3 g of 40% acrylamide aqueous solution and 10.7 g of 10% sodium methallylsulfonate aqueous solution were added. When the liquid temperature was stabilized at 80 ° C., 1.5 g of 20% ammonium peroxodisulfate aqueous solution was added and allowed to react for 30 minutes. It was.
Next, 60.3 g of 40% acrylamide aqueous solution and 10.7 g of 10% sodium methallyl sulfonate aqueous solution were added. When the liquid temperature was stabilized at 80 ° C., 2.4 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes. It was.
Next, the liquid temperature was raised to 90 ° C., and when stabilized, 2.9 g of a 20% aqueous ammonium peroxodisulfate solution was added and reacted for 120 minutes.
Thereafter, the mixture was cooled to room temperature, adjusted to pH 5 by adding an aqueous sodium hydroxide solution, and adjusted by adding ion-exchanged water so that the solid content concentration was 20% to obtain a copolymer of Preparation Example A-1. .
(“Clewat # 300A” is a sodium salt of ethylenediaminetetraacetic acid manufactured by Nagase ChemteX Corporation.)

Preparation Example A-2
In a 1 L four-necked separable flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas introduction tube, 68.0 g of the diallylamine lactate aqueous solution prepared in Preparation Example A-0, 24.2 g of 40% acrylamide aqueous solution, 2.6 g of 10% sodium methallylsulfonate aqueous solution, 1.7 g of 10% crewat # 300A aqueous solution and 333.8 g of ion-exchanged water were charged, and the temperature was raised to 80 ° C. while introducing nitrogen gas while stirring. When the liquid temperature was stabilized, 3.2 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 68.0 g of diallylamine lactate aqueous solution prepared in Preparation Example A-0, 24.2 g of 40% acrylamide aqueous solution, and 2.6 g of 10% sodium methallyl sulfonate aqueous solution were charged into the flask. When stabilized, 3.2 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 68.0 g of diallylamine lactate aqueous solution prepared in Preparation Example A-0, 24.2 g of 40% acrylamide aqueous solution, and 2.6 g of 10% sodium methallyl sulfonate aqueous solution were charged into the flask. When stabilized, 3.2 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 68.0 g of diallylamine lactate aqueous solution prepared in Preparation Example A-0, 24.2 g of 40% acrylamide aqueous solution, and 2.6 g of 10% sodium methallyl sulfonate aqueous solution were charged into the flask. When stabilized, 3.2 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 24.2 g of 40% acrylamide aqueous solution and 2.6 g of 10% sodium methallyl sulfonate solution were added into the flask. When the liquid temperature was stabilized at 80 ° C., 4.8 g of 20% ammonium peroxodisulfate aqueous solution was added. Reacted for 1 minute.
Next, 24.2 g of 40% acrylamide aqueous solution and 2.6 g of 10% sodium methallyl sulfonate solution were added into the flask. When the liquid temperature was stabilized at 80 ° C., 4.8 g of 20% ammonium peroxodisulfate aqueous solution was added. Reacted for 1 minute.
Next, the liquid temperature was raised to 90 ° C., and when stabilized, 9.6 g of a 20% aqueous ammonium peroxodisulfate solution was added and reacted for 120 minutes.
Thereafter, it was cooled to room temperature, adjusted to pH 5 by adding an aqueous sodium hydroxide solution, and adjusted by adding ion-exchanged water so that the solid content concentration was 20%, to obtain a copolymer of Preparation Example A-2. .

Preparation Example A-3
In a 1 L four-necked separable flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube, 113.5 g of diallylamine lactate aqueous solution prepared in Preparation Example A-0, 10.1 g of 40% acrylamide aqueous solution, 1.7 g of 10% crewat # 300A aqueous solution and 313.4 g of ion-exchanged water were charged, and the temperature was raised to 80 ° C. while introducing nitrogen gas while stirring. When the liquid temperature was stabilized, 6.3 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 10.1 g of 40% acrylamide aqueous solution was put into the flask, and when the liquid temperature was stabilized at 80 ° C., 6.3 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 113.5 g of diallylamine lactate aqueous solution prepared in Preparation Example A-0 and 10.1 g of 40% acrylamide aqueous solution were charged into the flask. When the liquid temperature was stabilized at 80 ° C., 6.3 g of 20% ammonium peroxodisulfate aqueous solution was added. Was allowed to react for 30 minutes.
Next, 10.1 g of 40% acrylamide aqueous solution was put into the flask, and when the liquid temperature was stabilized at 80 ° C., 6.3 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 113.5 g of diallylamine lactate aqueous solution prepared in Preparation Example A-0 and 10.1 g of 40% acrylamide aqueous solution were charged into the flask, and 6.3 g of 20% ammonium peroxodisulfate aqueous solution when the liquid temperature was stabilized at 80 ° C. Was allowed to react for 30 minutes.
Next, 10.1 g of 40% acrylamide aqueous solution was put into the flask, and when the liquid temperature was stabilized at 80 ° C., 6.3 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 10.1 g of 40% acrylamide aqueous solution was put into the flask, and when the liquid temperature was stabilized at 80 ° C., 6.3 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 10.1 g of 40% aqueous acrylamide solution and 0.7 g of 10% sodium methallyl sulfonate solution were charged into the flask. When the liquid temperature was stabilized at 80 ° C., 6.3 g of 20% aqueous ammonium peroxodisulfate solution was added. Reacted for 1 minute.
Next, the liquid temperature was raised to 90 ° C., and when stabilized, 12.6 g of a 20% aqueous solution of ammonium peroxodisulfate was added and reacted for 120 minutes.
Thereafter, the mixture was cooled to room temperature, adjusted to pH 5 by adding an aqueous sodium hydroxide solution, and adjusted by adding ion-exchanged water so that the solid content concentration was 20% to obtain a copolymer of Preparation Example A-3. .

<Preparation of diallylamine lactate-methacrylamide copolymer>
Preparation Example I-1
In a 1 L four-necked separable flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube, 68.0 g of diallylamine lactate aqueous solution prepared in Preparation Example A-0, 29.0 g of 40% methacrylamide aqueous solution. 2.6 g of 10% sodium methallylsulfonate aqueous solution, 1.7 g of 10% crewat # 300A aqueous solution and 333.8 g of ion-exchanged water were charged, and the temperature was raised to 80 ° C. while introducing nitrogen gas while stirring. When the liquid temperature was stabilized, 3.2 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 68.0 g of diallylamine lactate aqueous solution prepared in Preparation Example A-0, 29.0 g of 40% methacrylamide aqueous solution, and 2.6 g of 10% sodium methallylsulfonate aqueous solution were put into the flask, and the liquid temperature was 80 ° C. When stabilized, 3.2 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 68.0 g of diallylamine lactate aqueous solution prepared in Preparation Example A-0, 29.0 g of 40% methacrylamide aqueous solution, and 2.6 g of 10% sodium methallylsulfonate aqueous solution were put into the flask, and the liquid temperature was 80 ° C. When stabilized, 3.2 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 68.0 g of diallylamine lactate aqueous solution prepared in Preparation Example A-0, 29.0 g of 40% methacrylamide aqueous solution, and 2.6 g of 10% sodium methallylsulfonate aqueous solution were put into the flask, and the liquid temperature was 80 ° C. When stabilized, 3.2 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 29.0 g of 40% aqueous methacrylamide solution and 2.6 g of 10% sodium methallyl sulfonate solution were added to the flask, and 4.8 g of 20% aqueous ammonium peroxodisulfate solution was added when the liquid temperature was stabilized at 80 ° C. The reaction was allowed for 30 minutes.
Next, 29.0 g of 40% aqueous methacrylamide solution and 2.6 g of 10% sodium methallyl sulfonate solution were added to the flask, and 4.8 g of 20% aqueous ammonium peroxodisulfate solution was added when the liquid temperature was stabilized at 80 ° C. The reaction was allowed for 30 minutes.
Next, the liquid temperature was raised to 90 ° C., and when stabilized, 9.6 g of a 20% aqueous ammonium peroxodisulfate solution was added and reacted for 120 minutes.
Thereafter, the mixture was cooled to room temperature, adjusted to pH 5 by adding an aqueous sodium hydroxide solution, and adjusted by adding ion-exchanged water to a solid content concentration of 20%, to obtain a copolymer of Preparation Example I-1. .

Preparation Example I-2
In a 1 L four-necked separable flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, diallylamine lactate aqueous solution 113.5 g prepared in Preparation Example A-0, 40% methacrylamide aqueous solution 12.1 g 1.7 g of 10% crewat # 300A aqueous solution and 313.4 g of ion-exchanged water were charged, and the temperature was raised to 80 ° C. while introducing nitrogen gas while stirring. When the liquid temperature was stabilized, 6.3 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 12.1 g of 40% methacrylamide aqueous solution was put into the flask, and when the liquid temperature was stabilized at 80 ° C., 6.3 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 113.5 g of diallylamine lactate aqueous solution prepared in Preparation Example A-0 and 12.1 g of 40% methacrylamide aqueous solution were put into the flask, and when the liquid temperature was stabilized at 80 ° C., 20% ammonium peroxodisulfate aqueous solution 6. 3 g was added and reacted for 30 minutes.
Next, 12.1 g of 40% methacrylamide aqueous solution was put into the flask, and when the liquid temperature was stabilized at 80 ° C., 6.3 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 113.5 g of diallylamine lactate aqueous solution prepared in Preparation Example A-0 and 12.1 g of 40% methacrylamide aqueous solution were put into the flask, and when the liquid temperature was stabilized at 80 ° C., 20% ammonium peroxodisulfate aqueous solution 6. 3 g was added and reacted for 30 minutes.
Next, 12.1 g of 40% methacrylamide aqueous solution was put into the flask, and when the liquid temperature was stabilized at 80 ° C., 6.3 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 12.1 g of 40% methacrylamide aqueous solution was put into the flask, and when the liquid temperature was stabilized at 80 ° C., 6.3 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 12.1 g of 40% methacrylamide aqueous solution and 0.7 g of 10% sodium methallyl sulfonate solution were added into the flask, and 6.3 g of 20% ammonium peroxodisulfate aqueous solution was added when the liquid temperature was stabilized at 80 ° C. The reaction was allowed for 30 minutes.
Next, the liquid temperature was raised to 90 ° C., and when stabilized, 12.6 g of a 20% aqueous solution of ammonium peroxodisulfate was added and reacted for 120 minutes.
Thereafter, the mixture was cooled to room temperature, adjusted to pH 5 by adding an aqueous sodium hydroxide solution, and adjusted by adding ion-exchanged water so that the solid concentration was 20%, to obtain a copolymer of Preparation Example I-2. .

<Reference Example: Preparation of homopolymer of diallylamine lactate>
In a 1 L four-necked separable flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube, 213.5 g of diallylamine lactate aqueous solution prepared in Preparation Example A-0, 10% aqueous solution of Crewat # 300A 1. 7 g and ion-exchanged water 339.2 g were charged, and the temperature was raised to 80 ° C. while introducing nitrogen gas while stirring. When the liquid temperature was stabilized, 6.4 g of 20% ammonium peroxodisulfate aqueous solution was added and reacted for 30 minutes.
Next, 213.5 g of the diallylamine lactate aqueous solution prepared in Preparation Example A-0 was charged into the flask. When the liquid temperature was stabilized at 80 ° C., 6.4 g of a 20% ammonium peroxodisulfate aqueous solution was charged and allowed to react for 30 minutes. .
Subsequently, 8.0 g of 20% ammonium peroxodisulfate aqueous solution was further added and reacted for 30 minutes.
Next, the temperature of the solution was raised to 90 ° C., and when stable, 11.3 g of a 20% ammonium peroxodisulfate aqueous solution was added and reacted for 120 minutes.
Thereafter, the mixture was cooled to room temperature, adjusted to pH 5 by adding an aqueous sodium hydroxide solution, and adjusted by adding ion-exchanged water to a solid content concentration of 20%, to obtain a homopolymer of Reference Example.
With respect to this homopolymer, the reaction rate of diallylamine was confirmed by colloid titration. As a result, it was 34%, and the polymerization reaction was not sufficiently performed.

<Preparation of diallylamine acetate-acrylamide copolymer>
Preparation example B-0 of diallylamine acetate
Into a 1 L three-necked separable flask equipped with a stirrer, a thermometer, and a reflux condenser, 96.6% acetic acid 96.6 g and ion-exchanged water 548 g were charged and stirred. While cooling to 60 ° C. or lower, 155.5 g of diallylamine was added dropwise to prepare a 31.4% diallylamine acetate aqueous solution.

Preparation Example B-1
According to Preparation Example A-1, the reaction was carried out using the diallylamine acetate aqueous solution prepared in Preparation Example B-0 instead of the diallylamine lactate aqueous solution to obtain the copolymer of Preparation Example B-1.

<Preparation of diallylamine glycolate-acrylamide copolymer>
Preparation example C-0 of diallylamine glycolate
A 1 L three-necked separable flask equipped with a stirrer, a thermometer, and a reflux condenser was charged with 124.2 g of 98% glycolic acid and 520.4 g of ion-exchanged water and stirred. While cooling to 60 ° C. or lower, 155.5 g of diallylamine was added dropwise to prepare a 34.6% diallylamine glycolate aqueous solution.

Preparation Example C-1
In accordance with Preparation Example A-2, the reaction was carried out using the diallylamine glycolate aqueous solution prepared in Preparation Example C-0 instead of the diallylamine lactate aqueous solution to obtain the copolymer of Preparation Example C-1.

<Preparation of diallylamine formate-acrylamide copolymer>
Preparation example D-0 of diallylamine formate
A 1 L three-necked separable flask equipped with a stirrer, a thermometer, and a reflux condenser was charged with 75.2 g of 98% formic acid and 569.4 g of ion-exchanged water and stirred. While cooling to 60 ° C. or lower, 155.5 g of diallylamine was added dropwise to prepare a 28.6% diallylamine formate aqueous solution.

Preparation Example D-1
In accordance with Preparation Example A-3, the reaction was carried out using the diallylamine formate aqueous solution prepared in Preparation Example D-0 instead of the diallylamine lactate aqueous solution to obtain a copolymer of Preparation Example D-1.

<Preparation of diallylamine citrate-acrylamide copolymer>
Preparation example E-0 of diallylamine citrate
Into a 1 L three-necked separable flask equipped with a stirrer, a thermometer, and a reflux condenser, 204.9 g of 50% citric acid and 439.6 g of ion-exchanged water were charged and stirred. While cooling to 60 ° C. or lower, 155.5 g of diallylamine was added dropwise to prepare a 32.2% diallylamine citrate aqueous solution.

Preparation Example E-1
According to Preparation Example A-1, the reaction was carried out using the diallylamine citrate aqueous solution prepared in Preparation Example E-0 instead of the diallylamine lactate aqueous solution to obtain a copolymer of Preparation Example E-1.

<Preparation of diallylamine malate-acrylamide copolymer>
Preparation example F-0 of diallylamine malate
A 1 L three-necked separable flask equipped with a stirrer, a thermometer, and a reflux condenser was charged with 214.5 g of 50% malic acid and 430 g of ion-exchanged water and stirred. While cooling to 60 ° C. or lower, 155.5 g of diallylamine was added dropwise to prepare a 32.8% diallylamine malate aqueous solution.

Preparation Example F-1
In accordance with Preparation Example A-2, the reaction was carried out using the diallylamine malate aqueous solution prepared in Preparation Example F-0 instead of the diallylamine lactate aqueous solution to obtain the copolymer of Preparation Example F-1.

<Preparation of diallylamine hydrochloride-acrylamide copolymer>
Preparation example G-0 of diallylamine hydrochloride
A 1 L three-necked separable flask equipped with a stirrer, a thermometer, and a reflux condenser was charged with 166.6 g of 35% hydrochloric acid and 477.9 g of ion-exchanged water and stirred. While cooling to 60 ° C. or lower, 155.5 g of diallylamine was added dropwise to prepare a 26.7% diallylamine hydrochloride aqueous solution.

Preparation Example G-1
In accordance with Preparation Example A-3, the reaction was carried out using the diallylamine hydrochloride aqueous solution prepared in Preparation Example F-0 instead of the diallylamine lactate aqueous solution to obtain a copolymer of Preparation Example G-1.

<Preparation of polyallylamine lactate>
Preparation Example H-1
Add 50g of Nittobo PAA-15 (polyallylamine) and 22.9g of ion-exchanged water to a 200mL beaker, stir with a stirrer, and add 23.6g of 50% lactic acid slowly dropwise, and cool the solution to room temperature. The mixture was stirred until 20% polyallylamine lactate of Preparation Example H-1 was obtained.

(2) Preparation of pretreatment liquid Pretreatment liquids were prepared using the materials having the formulations shown in the respective columns of pretreatment liquids 1 to 17 in Table 1.
First, salts, a water-soluble organic solvent, a surfactant, and water were mixed and stirred for 30 minutes to mix uniformly. The cationic polymer was then added and stirred for 1 hour. Then, it filtered under pressure with a 0.8 micrometer cellulose acetate membrane filter, the coarse particle was removed, and the pretreatment liquid for evaluation was obtained. In addition, the meaning of the symbol in Table 1 is as follows. In addition, “2/8” in (DAA lactate / AAm = 2/8) represents a molar ratio, and the others are the same.
DAA: diallylamine PAA: polyallylamine AAm: acrylamide MAAm: methacrylamide PAS-92A: Nittobo, diallylamine acetate / sulfur dioxide copolymer
(Solid content 20%)
-Zonyl FSO-100: Fluorine nonionic surfactant manufactured by Dupont-Emulgen LS-106: Nonionic surfactant manufactured by Kao Corporation

<< Preparation of inkjet ink >>
(1) Preparation of Pigment Dispersion Preparation Example 1 (Preparation of surface-treated carbon black pigment dispersion)
CTAB specific surface area 150m ² / g, carbon black 90g of DBP oil absorption of 100 mL / 100 g, was added to 2.5 N sulfuric acid solution of sodium 3000 mL, 60 ° C., and stirred at a speed 300 rpm, the oxidized and reacted for 10 hours went. The reaction solution was filtered, and the carbon black separated by filtration was neutralized with a sodium hydroxide solution and subjected to ultrafiltration. The obtained carbon black was washed with water and dried, and dispersed in pure water so as to have a pigment concentration of 20% to obtain a carbon black pigment dispersion.

Preparation Example 2 (Preparation of surface-treated yellow pigment dispersion)
C. I. Pigment Yellow 128 was subjected to low-temperature plasma treatment to prepare a pigment having a carboxylic acid group introduced therein. The dispersion in ion-exchanged water was desalted and concentrated with an ultrafiltration membrane to obtain a yellow pigment dispersion having a pigment concentration of 15%.

Preparation Example 3 (Preparation of surface-treated magenta pigment dispersion)
C. I. A surface-modified magenta pigment was prepared in the same procedure as in Preparation Example 2 except that Pigment Red 122 was used instead of Pigment Yellow 128 to obtain a magenta pigment dispersion having a pigment concentration of 15%.

Preparation Example 4 (Preparation of surface-treated cyan pigment dispersion)
C. I. Instead of CI Pigment Yellow 128, C.I. I. A surface-modified cyan pigment was prepared in the same procedure as in Preparation Example 2, except that CI Pigment Cyan 15: 3 was used, and a cyan pigment dispersion having a pigment concentration of 15% was obtained.

Synthesis Example 1 (Preparation of polymer solution)
After sufficiently replacing nitrogen gas in the 1 L flask equipped with a mechanical stirrer, thermometer, nitrogen gas inlet tube, reflux tube and dropping funnel, 11.2 g of styrene, 2.8 g of acrylic acid, 12.0 g of lauryl methacrylate, Polyethylene glycol methacrylate 4.0 g, styrene macromer 4.0 g, mercaptoethanol 0.4 g, and methyl ethyl ketone 40 g were mixed and heated to 65 ° C.
Next, 100.8 g of styrene, 25.2 g of acrylic acid, 108.0 g of lauryl methacrylate, 36.0 g of polyethylene glycol methacrylate, 60.0 g of hydroxylethyl methacrylate, 36.0 g of styrene macromer, 3.6 g of mercaptoethanol, azobismethylvaleronitrile A mixed solution of 2.4 g and methyl ethyl ketone 342 g was dropped into the flask over 2.5 hours.
After dropping, a mixed solution of 0.8 g of azobismethylvaleronitrile and 18 g of methyl ethyl ketone was dropped into the flask over 0.5 hours. After aging at 65 ° C. for 1 hour, 0.8 g of azobismethylvaleronitrile was added and further aging was performed for 1 hour.
After completion of the reaction, 800 g of a polymer solution having a concentration of 50% was obtained.

Preparation Example 5 (Preparation of aqueous dispersion of phthalocyanine pigment-containing polymer fine particles)
17.5 g of the polymer solution prepared in Synthesis Example 1, C.I. I. 32.5 g of CI Pigment Blue 15: 3, 8.5 g of 1 mol / L potassium hydroxide aqueous solution, 13 g of methyl ethyl ketone and 13.6 g of ion-exchanged water were sufficiently stirred, and then kneaded using a roll mill.
The obtained paste was put into 200 g of pure water and stirred sufficiently, and then methyl ethyl ketone and water were distilled off using an evaporator to obtain an aqueous dispersion of cyan pigment-containing polymer fine particles containing 15% pigment and 20% solids. Obtained.

Preparation Example 6 (Preparation of aqueous dispersion of polymer fine particles containing dimethylquinacridone pigment)
17.5 g of the polymer solution prepared in Synthesis Example 1, C.I. I. 32.5 g of Pigment Red 122, 8.5 g of 1 mol / L potassium hydroxide aqueous solution, 13 g of methyl ethyl ketone and 13.6 g of ion-exchanged water were sufficiently stirred, and then kneaded using a roll mill.
The obtained paste was put into 200 g of pure water and stirred sufficiently, and then methyl ethyl ketone and water were distilled off using an evaporator to obtain an aqueous dispersion of magenta pigment-containing polymer fine particles containing 15% pigment and 20% solids. Obtained.

Preparation Example 7 (Preparation of aqueous dispersion of polymer fine particles containing monoazo yellow pigment)
28.0 g of the polymer solution prepared in Synthesis Example 1, C.I. I. 26.0 g of Pigment Yellow 74, 13.6 g of a 1 mol / L potassium hydroxide aqueous solution, 20 g of methyl ethyl ketone and 13.6 g of ion-exchanged water were sufficiently stirred, and then kneaded using a roll mill.
The obtained paste was put into 200 g of pure water and stirred sufficiently, and then methyl ethyl ketone and water were distilled off using an evaporator to prepare an aqueous dispersion of yellow pigment-containing polymer fine particles containing 15% pigment and 20% solids. Obtained.

Preparation Example 8 (Preparation of aqueous dispersion of carbon black pigment-containing polymer fine particles)
28 g of the polymer solution prepared in Synthesis Example 1, CTAB specific surface area of 150 m ² / g, DBP oil absorption of 100 mL / 100 g of carbon black 26.0 g, 1 mol / L of potassium hydroxide aqueous solution 13.6 g, methyl ethyl ketone 20 g and ion exchange After sufficiently stirring 13.6 g of water, the mixture was kneaded using a roll mill.
The obtained paste was put into 200 g of pure water and stirred sufficiently, and then methyl ethyl ketone and water were distilled off using an evaporator to obtain an aqueous dispersion of black pigment-containing polymer fine particles containing 15% pigment and 20% solids. Obtained.

Preparation Example 9 (Preparation of phthalocyanine pigment dispersion)
C. I. 150 g of CI Pigment Cyan 15: 3, 110 g of β-naphthol ethylene oxide 40 mol adduct, 2 g of Pionein A-51-B (manufactured by Takemoto Yushi Co., Ltd.) and 738 g of distilled water were mixed and the mixture was pre-dispersed. The mixture was circulated and dispersed for 20 hours using a type of bead mill (KDL type, manufactured by Shinmaru Enterprises, media: 0.3 mmφ zirconia ball used) to obtain a cyan pigment dispersion.

Preparation Example 10 (Preparation of dimethylquinacridone pigment dispersion)
C. I. Pigment Cyan 15: 3, C.I. A magenta pigment dispersion was obtained in the same manner as in Preparation Example 9 except that it was changed to I Pigment Red 122.

Preparation Example 11 (Preparation of monoazo yellow pigment dispersion)
C. I. Pigment Cyan 15: 3, C.I. A yellow pigment dispersion was obtained in the same manner as in Preparation Example 9 except that it was changed to I Pigment Yellow 74.

Preparation Example 12 (Preparation of carbon black pigment dispersion)
200 g of carbon black having a CTAB specific surface area of 150 m ² / g and DBP oil absorption of 100 mL / 100 g, 50 g of Pionine A-45-PN (condensate of naphthalene sulfonate formalin) and 750 g of distilled water are mixed, and this mixture is pre-dispersed. Then, it was circulated and dispersed for 20 hours in a disk-type bead mill (KDL type, manufactured by Shinmaru Enterprises, media: 0.3 mmφ zirconia ball used) to obtain a black pigment dispersion.

(2) Preparation of polymer fine particle dispersion After thoroughly substituting the inside of a 1 L flask equipped with a mechanical stirrer, thermometer, nitrogen gas introduction tube, reflux tube and dropping funnel with nitrogen gas, 8.0 g of Latemule S-180 was added. Then, 350 g of ion exchange water was added and mixed, and the temperature was raised to 65 ° C. After temperature increase, 3.0 g of reaction initiator t-butyl peroxobenzoate and 1.0 g of sodium isoascorbate were added, and after 5 minutes 45 g of methyl methacrylate, 160 g of 2-ethylhexyl methacrylate, 5 g of acrylic acid, butyl methacrylate 45 g, 30 g of cyclohexyl methacrylate, 15 g of vinyltriethoxysilane, 8.0 g of Latemule S-180 and 340 g of ion-exchanged water were mixed and added dropwise over 3 hours. Thereafter, the mixture was aged by heating at 80 ° C. for 2 hours, cooled to room temperature, and adjusted to pH 7-8 with sodium hydroxide. Ethanol was distilled off using an evaporator, and the water content was adjusted to obtain 730 g of a polymer fine particle dispersion having a solid content of 40%.

(3) Preparation of ink Inks were prepared using materials having the formulations shown in the respective columns of inks 1 to 16 in Table 2.
First, a water-soluble organic solvent, a surfactant, and water were mixed and stirred for 30 minutes to mix uniformly.
Next, the pigment dispersion or the pigment-containing polymer fine particle dispersion of the above preparation example is added, and in the inks 1 to 5, the polymer fine particle dispersion is further added, and the remaining amount of water is added so that the total amount becomes 95%. Stir for minutes.
Next, a 10% aqueous solution of lithium hydroxide was added to adjust the pH to 9, and the remaining amount of water was added so that the total amount would be 100%, followed by stirring for 1 hour.
Subsequently, it filtered under pressure with a 0.8 micrometer cellulose acetate membrane filter, the coarse particle was removed, and the evaluation ink was obtained.

上記表２中の商品名で示された材料の詳細は次のとおりである。
・ハイドランＷＬＳ２１３：ＤＩＣ社製、ウレタンアイオノマー
・タケラックＷ５６６１：三井化学社製、ウレタンアイオノマー

Details of the materials indicated by the trade names in Table 2 are as follows.
・ Hydrane WLS213: Urethane ionomer manufactured by DIC ・ Takelac W5661: Urethane ionomer manufactured by Mitsui Chemicals

<< Image formation and evaluation >>
The pretreatment liquid of Table 1 and the ink of Table 2 were used as a set as shown in Table 3, and image formation was performed for evaluation. The image forming method and evaluation contents are as follows.
The results are shown in Table 4, and the evaluation was performed for each color, and the results of each image quality described the most frequent determination results. In the case of the same number of determination results, the better one is described.
Note that “black square” is a black square that is filled in, but because the character cannot be used, it is expressed as such.

<Image formation>
Evaluation was performed in an environment adjusted to a temperature of 23 ± 0.5 ° C. and 50 ± 5% RH.
For the pretreatment, the roll coater shown in FIG. 4 is used, the nip pressure and the coating speed are changed in accordance with the pretreatment liquid, and the coating amount is adjusted so that the wet amount is 0.8 g / m ^2. Coated on top.
For printing, an inkjet printer (IPSiO GX5000, manufactured by Ricoh) was used, and the drive voltage of the piezo element was varied so that the amount of ink discharged was uniform, so that the same amount of ink was attached to the recording medium. I went.
For image output, printing was performed within 1 minute after application of the pretreatment liquid to produce an evaluation image.
As recording media, recycled PPC (recycled paper) manufactured by Daio Paper Co., Ltd .: basis weight 66.5 g / m ² , waste paper pulp content 70% or more, sizing 17 seconds, and air permeability 35 seconds were used.

<Image density>
A chart with 64 point characters “black square” created by Microsoft Word 2000 is printed on a recording medium, and the “black square” portion of the printed surface is measured with X-Rite 938 (spectral colorimeter manufactured by X-Rite). The determination was made according to the following evaluation criteria. The printing mode was “plain paper-clean” mode and color matching off with a driver attached to the printer.
〔Evaluation criteria〕
A: Black: 1.45 or more,
Yellow: 0.90 or more,
Magenta: 1.15 or higher,
Cyan: 1.20 or more ○: Black: 1.35 or more, less than 1.45,
Yellow: 0.85 or more, less than 0.90,
Magenta: 1.05 or more, less than 1.15,
Cyan: 1.10 or more and less than 1.20 ×: Black: less than 1.35
Yellow: less than 0.85,
Magenta: less than 1.05
Cyan: Less than 1.10

<Betrayal density>
A chart with 64 point characters “black square” created by Microsoft Word 2000 is printed on the recording medium, and the back side “black square” portion of the printing surface is measured by X-Rite 938, and the recording medium background density is subtracted. Was determined according to the following evaluation criteria. The printing mode was “plain paper-clean” mode and color matching off with a driver attached to the printer.
〔Evaluation criteria〕
: Black: Less than 0.09
Yellow: less than 0.08
Magenta: less than 0.09,
Cyan: Less than 0.09 ○: Black: 0.09 or more, less than 0.10
Yellow: 0.08 or more, less than 0.09,
Magenta: 0.09 or more, less than 0.10,
Cyan: 0.09 or more, less than 0.10 ×: Black: 0.10 or more,
Yellow: 0.09 or more
Magenta: 0.10 or higher,
Cyan: 0.10 or more

<Color bleed>
“Color border bleeding” occurs when recording images are formed with evaluation images having 0.5 mm line images of magenta, cyan, and black in yellow solid images, and inks of different colors adjoin each other. The occurrence of was observed visually and judged according to the following criteria. Similarly, when an evaluation image having magenta, yellow, and black line images of 0.5 mm is formed in a cyan solid image, and 0.5 mm lines of cyan, yellow, and black are formed in the magenta solid image. In the case where each image was formed as an evaluation image, the occurrence of “color boundary bleeding” was observed and judged according to the following criteria.
〔Evaluation criteria〕
A: No problem at all.
○: Slight occurrence but no problem.
X: Occurs to the extent that becomes a problem.

<Text blur>
A chart with a 6-point character “轟” written by Microsoft Word 2000 was printed on a recording medium, and the occurrence of “character bleeding” was visually observed and judged according to the following criteria.
〔Evaluation criteria〕
A: No problem at all.
○: Slight occurrence but no problem.
X: Occurs to the extent that becomes a problem.

<Solid filling>
A chart with 64 point characters “black square” created by Microsoft Word 2000 is printed on a recording medium, and the presence of “white spots” in the “black square” solid image portion of the yellow, magenta, cyan, and black print surface is visually confirmed. Observed and judged according to the following criteria.
〔Evaluation criteria〕
A: No problem at all.
○: Slightly present but no problem.
Δ: Although there is no problem within the allowable range.
×: There is a problem.

<Smear fixability>
A chart with a solid black solid image of 3 cm × 3 cm created by Microsoft Word 2000 was shot on a recording medium, dried at a temperature of 23 ± 1 ° C. and a humidity of 50 ± 10% for 24 hours, and the “black square” portion of the printing surface was Using JIS L 0803 cotton 3 attached to the CM-1 type clock meter with double-sided tape, it was reciprocated 5 times so that it hits the print site, and then the ink adhesion stain on the cotton cloth was measured with X-Rite 938. The skin color was subtracted, and the density of the soiled area was determined according to the following criteria.
〔Evaluation criteria〕
○: Less than 0.15 Δ: 0.15 or more and less than 0.25 ×: 0.25 or more

<Drying> (Smear fixing immediately after printing)
Immediately after launching a chart with a 3cm x 3cm mono black solid image created by Microsoft Word 2000 on a recording medium (after 10 seconds), the "black square" part of the printing surface is attached to a CM-1 type clock meter with double-sided tape. After using the JIS L 0803 cotton No. 3 attached in step 5 to reciprocate 5 times so that it touches the print site, the ink adhesion stain on the cotton cloth is measured with X-Rite 938, and the background color of the cotton cloth is subtracted. The concentration was determined according to the following criteria. (Evaluation environment: temperature 23 ± 1 ° C, humidity 50 ± 10%)
〔Evaluation criteria〕
○: Less than 0.2 Δ: 0.02 or more and less than 0.3 ×: 0.3 or more

<Liquid contamination>
A SUS403 tempered material (hardened at 950 ° C. and tempered at 700 ° C.) was used, and the surface was polished with sandpaper # 100 and surface-finished with # 600 to obtain a test piece. The absorbance of this test piece was measured at 500 nm with an ultraviolet-visible absorption spectrum spectrometer. Next, the test piece was immersed in a pretreatment liquid having a weight (g) 10 times its surface area (cm ² ) for 1 month at 50 ° C., and the absorbance was measured in the same manner. The coloration of the liquid was determined based on the following criteria based on the change in absorbance before and after immersion. The above as "surface area 10 times the weight of (cm ²⁾ (g)" is the weight obtained by the formula "surface area (cm ²⁾ × weight of the liquid used in the 10 = immersion (g)", Corrosion Since the degree of corrosion is determined according to the surface area because it proceeds from the surface, the amount of immersion liquid is defined based on the surface area in order to keep the liquid amount constant.
〔Evaluation criteria〕
○: Less than 0.1 Δ: 0.1 or more and less than 0.5 ×: 0.5 or more

<Corrosive>
After immersion for 1 month at 50 ° C. in the same manner as in the liquid contamination test, determination was made according to the following criteria according to the surface condition of the test piece.
〔Evaluation criteria〕
○: No change in state. There is slight surface corrosion. (No change in appearance)
Δ: There is fine corrosion on the surface but no vertical erosion. (The surface is cloudy)
X: There is corrosion in the vertical direction.

In each of Examples 1 to 14, the image density, the back-through density, the color bleed, and the character bleeding were satisfied, and the solid filling, smear fixing property, and drying property were satisfied.
On the other hand, Comparative Examples 1 to 3 had good show-through density, color bleed, and character bleeding, but had poor image density, solid filling, smear fixing property, and drying property.
Based on the above results, the pretreatment liquid containing a copolymer of diallylamine organic acid salt and (meth) acrylamide satisfies the image density, solid filling, smear fixability, and dryness, while exhibiting the back-through density, color bleeding, text bleeding. Was found to provide a good image.
Moreover, Examples 1-3, 5, 7-11, and 13-14 which concern on the pretreatment liquid containing the copolymer of the diallylamine organic acid salt using a hydroxy acid and (meth) acrylamide are good at the point of solid filling. It was found that a pretreatment liquid containing a cationic polymer using a hydroxy acid for neutralization among organic acids can provide a better image. Since Example 12 did not contain a surfactant, the solid filling was Δ.

DESCRIPTION OF SYMBOLS 1 Pretreatment liquid 2 Film thickness control roller 3 Pumping roller 4 Application roller 5 Counter roller 6 Recording medium 7 Paper feed roller 8 Paper feed tray 10 Paper feed roller 11 Recording media feed roller 12 Recording media feed roller 13 Recording media feed Roller 14 Recording media feed roller 15 Recording media feed roller 16 Recording media feed roller 17 Recording media 18 Paper feed roller 20 Recording head 21 Ink cartridge 22 Carriage shaft 23 Carriage 31 Recording media guide 32 Recording media feed roller 33 Recording media feed roller 34 Recording media return guide 35 Paper feed guide 101 Pretreatment liquid 102 Recording media 103 Vehicle contained in ink jet ink 104 Pigment (aggregate)
201 Pretreatment liquid 202 Pumping roller 203 Applying roller 204 Counter roller 205 Recording medium 206 Pretreatment liquid tank 207 Paper feed tray 208 Paper discharge tray

Japanese Patent No. 3206797 Japanese Patent Application No. 2010-184212

Claims (5)

  A pretreatment liquid used for ink jet recording, comprising at least a cationic polymer comprising diallylamine organic acid salt and (meth) acrylic acid amide as constituent components, a water-soluble organic solvent, and water.   The pretreatment liquid according to claim 1, wherein the (meth) acrylic acid amide contains acrylamide.   The pretreatment liquid according to claim 1, wherein the organic acid contains a hydroxy acid.   The pretreatment liquid according to any one of claims 1 to 3, further comprising an organic acid ammonium salt or an organic acid amine salt.   The pretreatment liquid according to claim 4, wherein the organic acid ammonium salt or organic acid amine salt is an ammonium lactate salt or a lactate amine salt.

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